Citing Sources

Why We Cite

Citing sources increases your own credibility: because you are most likely not a world-renowned expert on your topic, you need to bring in evidence from people who are. It shows you have done your research. Citations allow readers who are curious (or skeptical!) to find your sources and learn more. And of course, a failure to cite sources is plagiarism, a serious academic offense.

Cite ALL the Sources! You don't want to make this guy angry, do you? I didn't think so.


Source: Today I Stared a Camel in the Face by Adam Foster under a Creative Commons license

What to Cite

Any time you use ideas and information from a source, it needs to be cited. If you are using the EXACT WORDS of an original source, they must appear in quotation marks, even if it is just a brief phrase. Otherwise, paraphrase or summarize the source, putting the information into YOUR OWN words. Either way requires an in-text citation. The exceptions to this are common knowledge and your own conclusions; see Avoiding Plagiarism for more.

You must also cite any IMAGES you use, even in creative projects. To find media that you have permission to use outside the classroom, such as on a website, look for images with Creative Commons licenses or in the public domain.

Research Tip

Expert opinions add authority and weight to your claims but should be used primarily as evidence and support for YOUR argument. The argument itself should be presented using your own words and ideas. Think of it as participating in a discussion with your sources. This is a difficult balancing act for most student researchers, but your confidence will increase as you learn more about your topic.

Sources are also useful for explaining background information or establishing a context for your research. Finally, consider including sources that present the opposite side to your position, which can provide an opportunity for you to write a counterargument.

How to Cite

With few exceptions, teachers at Arlington High School use the Modern Language Association (MLA) style, which has two parts:

  1. Brief in-text citations so the reader can find the source in your Works Cited list

  2. A detailed list of Works Cited at the end of the paper

The in-text citation identifies the work being used, usually by author’s name in a signal phrase or in a parenthetical citation. For example, this might appear in the body of a paper:

  • Although DNA testing for future illnesses may feel like a death sentence, the truth is that "genetics is not destiny," and many mutations never result in symptoms (Maron 28).

  • Dina Fine Maron notes that although DNA testing for future illnesses may feel like a death sentence, the truth is that "genetics is not destiny," and many mutations never result in symptoms (28).

This points the reader to the following entry in the Works Cited page:

  • Maron, Dina Fine. "When DNA Means Do Not Ask." Scientific American, vol. 213, no. 1, Jan. 2015, pp. 28-30.

See In-Text Citations and Works Cited Page for details and use our subscription to NoodleTools to help.

Other Citation Styles: APA

There are a few classes at Arlington High School where the American Psychiatric Association (APA) style is used. If this is the case, your teacher will tell you.

This choice reflects different priorities and traditions in the disciplines. For example, APA format includes the date of publication in the parenthetical citation, because currency is considered to be more important than in MLA format, which is widely used in the humanities.

Learn more about how to use APA format from the Online Writing Lab (OWL) at Purdue University. The school's subscription to NoodleTools also supports APA format. If you have questions, ask your teacher or a librarian for help.